Which  graph represents the solution set of the system of inequalities? x+y< 1 2y≥x−4   i think its the one in the top right corner (the highlighted one)

Solve first for the solution of the inequalities. This can be done by replacing first the inequalities sign with the equal sign. 

x + y = 1
2y = x - 4

The values of x and y from the system of linear equation are 2 and -1. This means that the intersection of the lines should be at point (2, -1). 

Substitute 3 to x and determine the value of y from the second inequality.
 2y ≥ x - 4

Substituting,
  2y ≥ 3 - 4, y ≥ -1/2

Hence, the solution to this item should be the fourth one.